Yaesu FTdx5000MP, Руководство по эксплуатации

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Page 63 FT
DX
5000 O
PERATING
M
ANUAL
I
NTERFERENCE
R
EJECTION
(
S
IGNALS WITHIN
3
KHZ
)
IF N
OTCH
F
ILTER
O
PERATION
(
SSB/CW/RTTY/PKT/AM M
ODES
)
The IF Notch filter is a highly effective system that allows you to slice out an interfering beat note or other carrier signal
from inside the receiver passband.
VFO-A IF Notch Operation
Press the (
VFO-A
)[
NOTCH
] button. The (
VFO-
A
)[
NOTCH
] button glows red, and the current “null”
(or “Peak”) position of the IF notch filter will appear
in the
SUB DISPLAY- II window. The ( VFO-
A )[ SELECT ] knob will now function as the notch
adjustment knob.
Rotate the (
VFO-A
)[
SELECT
] knob to adjust the cen-
ter frequency of the IF notch filter.
Press the (
VFO-A
)[
RESET
] button to move the “null”
position to center.
To switch the IF notch filter off, press the (
VFO-
A
)[
NOTCH
] button once more.
The affect of rotation of the [ SELECT
](notch)
knob on the performance of the IF notch filter is
depicted in Figure “
A ”. In Figure “ B ”, you can see
the notching effect of the IF notch filter as you ro-
tate the [
SELECT
](notch) knob to eliminate the
incoming interference.
VFO-B IF Notch Operation
Press the (
VFO-B
)[
NOTCH
] button. The (
VFO-
B
)[
NOTCH
] button glows red, and current “null” (or
“Peak”) position of the IF notch filter will be indicated
in the
SUB DISPLAY- III window. The ( VFO-
B )[ SELECT ] knob will now function as the notch
adjustment knob.
Rotate the (
VFO-B
)[
SELECT
] knob to adjust the cen-
ter frequency of the IF notch filter.
Press the (
VFO-B
)[
RESET
] button to move the “null”
position to center.
To switch the IF notch filter off, press the (
VFO-
B
)[
NOTCH
] button once more.
A
DVICE
:
The width of the IF notch null may be adjusted using
Menu item “
110 RDSP NOTCH WI
”. Both “Wide”
and “Narrow” selections are available, with “Narrow”
providing the least disruption of the “desired” signal.
You may select the display pattern shown in the
SUB
DISPLAY window from three patterns via Menu item
“ 019 DISP SELECT ”. See page 122 for details.
When the optional DMU-2000 Data Management Unit
is connected, the effect of the IF notch filter may be
observed using the Audio Scope (on the “Oscilloscope”
page). The notch will be seen as a “dip” in the noise
platform observed. What’s more, the “Waterfall” dis-
play may be used to observe the effect of the IF notch
filter, which will appear as a white area in the colored
background. The tuning rate for the IF notch is some-
what slow while you adjust the [
SELECT
](notch)
knob, so the use of the Waterfall display to confirm
proper adjustment is highly recommended.
(VFO-A)[SELECT] Knob
[RESET] Button
(VFO-A)[NOTCH] Button
(VFO-B)[SELECT] Knob
[RESET] Button
(VFO-B)[NOTCH] Button
IF
BANDWIDTH
QRM
(Heterodyne)
QRM
(Heterodyne)
IF
BANDWIDTH
Desired Signal Desired Signal
A B